Red Bull chief technical officer Adrian Newey says the new RB9 is hard to judge despite the relative stability in regulations over the winter.

The new car was unveiled at Red Bull's headquarters in Milton Keynes on Sunday, and will make its track debut on Tuesday at the first test at Jerez. However, when asked how good he thought the RB9 would be, Newey said the dependence on simulators means even the performance of the finished car was impossible to know in the early part of the season despite it being an evolution of the RB8.

"I always find it an incredibly hard thing to answer, for various reasons," Newey said. "First of all we know what we believe we've done over the winter in terms of what our simulation results have given us, so obviously we feel we've made a small step forwards otherwise there would be no point in producing a new car. But we don't know what everyone else has done, we don't know how much they've stepped forwards, and we don't know if our simulation results are 100% accurate; that's the nature of simulation.

"Almost by definition there will be errors. Sometimes those errors can be in the positive sense - rarely I have to say - other times suddenly you have problems where perhaps with what we've predicted in the wind tunnel this winter bear out on track. These new Pirelli tyres I'm sure will change the characteristics of the car, so there's a lot of unknowns which will sort of come out in pre-season testing and the early races."

Newey added that even if the car was dominant at the start of the season, the nature of the development race means there's no guarantee that will automatically lead to success.

"I think what's really characterised and changed Formula One in the last ten or more years is the rate of development throughout the year. It used to be if you came out with a dominant car at the start of the year then - as long as it was reliable - you could probably reckon you're going to win the championship. That's not the case anymore; teams will come back, they can outdevelop other teams, it really is a continual development. Certainly in this situation where we have got stable regulations, actually a new car you can almost picture it as another evolution, another race; it just so happens that we've had three months between races instead of two weeks."

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